But I am using graph api directly in iOS, I can't find where to set this flag, I tried to set it when create the album and when upload the image, but it didn't work.

Facebook graph API reference (http://developers.facebook.com/docs/reference/api/album/) said can_upload must be true for an album to allow upload photos to the album, I checked the album that I tried to upload the image and it is true.

I also have permission of user_photos, friends_photos, publish_stream, publish_actions.

Below is my code to post the image, I have spent a lot of time on this but can't fix it, plz help me! any help is appreciated.